T: Temperature;  F0: Sterilisation time at reference temperature 121 C, needed to achive the sterility criterion;

LR: Lethal rate;  Facc: Accumulated sterilisation dose.

This SIMSPEC file calculates the accumulated sterilisation dose (Facc) from a temperature curve. In this case an experimental temperature curve was used. If such data are not available the program produces a simple fake curve for demonstration. The lethal rate is obtained from the assumed D-value and Z-value of the organism. Alternatively, the first order inactivation rate constant and the Arrhenius equation can be used.  The sterility criterion is reached when the Facc value reaches the F0 value. In this case the simulation was stopped at this point. Alternatively, the Facc contribution during the cooling period can also be included, which may be relevant when the cooling is slow.

Thetheory of sterilisation kinetics is included in Fermentation Process Engineering, 2nd ed. (will become available for downloading from www.enfors.eu.